PBMAC-Position Based Channel Allocation for Vehicular Ad Hoc Networks

In Vehicular ad hoc networks road safety and traffic management applications required stable communication channel with minimum disturbances. In vanets vehicles used bandwidth to forward packets towards destination with the help of relay nodes. While exchanging information there are chances of collisions due to improper bandwidth allocation in a network. Some applications such as safety and traffic management required consistent channel conditions. However the design of an efficient medium access control (MAC) is a challenging task due to dynamic topology changes. The existing cluster based TDMA MAC protocols used traffic loads for bandwidth allocation in such a manner position of vehicle in the cluster is not considered. As part of that, vehicles located at end of cluster region can request for channel, as consequence the cluster head (CH) allocates bandwidth based on traffic loads. In this case vehicles are not in a stage to use total reserved slot allocated for usage, because in short span vehicles move to next cluster region, it shows inefficient allocation of channel. In this paper we proposed an efficient approach for allocation of bandwidth which depends on vehicle position in cluster. Here vehicles at starting position can get more bandwidth when compare to end position vehicles. The simulation shows position based bandwidth allocation where the channel is allocated based on effective and reduces collisions as result improves overall network performance.